Parasite food vacuole heme pool (FPPIX pool)

The parasite food vacuole heme pool refers to the accumulation of ferriprotoporphyrin IX (FPPIX), a toxic byproduct generated during the digestion of host hemoglobin by Plasmodium species [Egan, 2008]. Within the acidic digestive vacuole, the parasite must rapidly detoxify this free heme by sequestering it into an insoluble, non-toxic crystalline polymer known as hemozoin [Sullivan, 2002]. This process is a critical survival mechanism for the malaria parasite during its intraerythrocytic developmental stage [Wunderlich et al., 2012]. Many classic antimalarial drugs, such as chloroquine and other quinolines, exert their therapeutic effect by interfering with this biocrystallization process [Hempelmann, 2007]. By binding to the heme monomers or the surface of growing hemozoin crystals, these drugs prevent detoxification, leading to the accumulation of membrane-lytic and oxidative heme species that ultimately kill the parasite [Sigala & Goldberg, 2014]. Consequently, the heme pool represents one of the most successful and clinically validated targets in the history of antimalarial chemotherapy [Combrinck et al., 2013].

Other names

Ferriprotoporphyrin IX poolFPPIX poolLabile heme poolDigestive vacuole hemeHeme pool

Inhibition of heme biocrystallization into hemozoin, leading to the accumulation of toxic free heme (ferriprotoporphyrin IX) which causes oxidative damage and parasite death [Egan, 2008; Sullivan, 2002].